Optimization of a microbolometer pixel for operation in the sub-1 THz region


Demirörs O., Atik B., Dirican E., ALTAN H., ESENTÜRK O., Ylldlrlm M., ...More

Terahertz Emitters, Receivers, and Applications XII 2021, California, United States Of America, 1 - 05 August 2021, vol.11827 identifier

  • Publication Type: Conference Paper / Full Text
  • Volume: 11827
  • Doi Number: 10.1117/12.2594067
  • City: California
  • Country: United States Of America
  • Keywords: Absorber, Absorption, Effective medium, Resonant, Terahertz, Thin-film

Abstract

© 2021 SPIE.Imaging in the Terahertz (THz) region has drawn attention in recent years, but the nature of the THz frequency regime causes some drawbacks in imaging such as long wavelength, high cost, and low emission levels at room temperature. Because of the high atmospheric absorption of THz waves, fabrication of a microbolometer pixel that works in the sub-1 THz frequency regime is necessary. Large pixel pitches due to longer wavelengths and the resulting higher thermal mass pose a difficult challenge. Due to those limitations, a unique design of an absorber is essential for THz microbolometers. This study investigates the use of absorbers based on novel materials and alloys with the goal of developing efficient absorbers in small pixel pitches. First, thin layer metal absorbers typically used in commercial IR microbolometers are characterized in terms of absorption performance in the sub-1 THz region. Thin films based on metal alloys such as TiAlV show a markedly lower absorption in this region than in the IR. To improve the performance of these absorbing layers and reduce pixel pitches. Use of effective media based on the mixture of dielectric materials and metals with patterned thin films are investigated to develop unique absorbing thin layers. It is seen that with the use of an effective medium whose complex dielectric constant is tailored appropriately, efficient absorption of sub-1 THz radiation can be achieved.